Hydraulic Cylinders for Use in Aviation and Aircraft
Hydraulic cylinders are heavy duty pushers, pullers, and lifters, and are therefore critical pieces of equipment for the aviation industry. Hydraulic cylinder applications include:
- Landing gear control
- Flight control surfaces
- Cargo door control
- Aircraft braking systems
Hydraulic cylinders are involved in extremely important aircraft functions, so they must offer excellent reliability. Here, we’ll address how hydraulic cylinders are used in aircraft and how aviation companies can maintain them.
What are Some Common Hydraulic Cylinder Applications in the Aviation Industry?
Hydraulic cylinders play a number of important roles in aviation, including:
- Controlling the landing gears – Hydraulic cylinders are responsible for actuating the aircraft’s landing gears by raising or lowering them as needed. Hydraulic systems are built with redundancies in place, so if one piece of hydraulic equipment experiences a failure, the system can still be controlled. This is the case for most aircraft landing systems and flight surfaces.
- Controlling the aircraft’s flight surfaces – Flight surfaces refer to the aircraft’s flaps, ailerons, elevators, and rudders – the parts that control the plane’s altitude. Hydraulic actuators are used to make fine adjustments to each, allowing pilots maximum control of the aircraft’s altitude.
- Controlling and adjusting the aircraft’s cargo doors – Even when the aircraft isn’t in the air, hydraulic cylinders may still be at work. For example, they’re responsible for lifting and lowering the plane’s cargo doors.
- Controlling the aircraft’s brakes – While the aircraft is landing or taxiing, the pilots use hydraulic power to engage its brakes. Hydraulic cylinders used in aircraft brakes must be capable of handling extreme loads and challenging environmental conditions.
Three Reasons Why Hydraulic Cylinders are Used in Aviation Systems
Hydraulics are irreplaceable in aviation and are typically preferred to pneumatics for several reasons. Three of those reasons include:
- Better actuator control – Hydraulics are uniquely well-suited to aviation applications because hydraulic fluid doesn’t compress like air. It maintains its density at varying levels of environmental pressure – helpful for a vehicle that experiences massive pressure swings during transit. With hydraulics, flight controls remain consistent and smooth at every altitude, so pilots don’t have to adjust how they’re handling those controls. In flight school, pilots are taught to apply subtle force when controlling the aircraft to prevent overcompensating. Hydraulic cylinders align with this idea.
- Excellent reliability – Hydraulic cylinders used in aviation are extremely reliable. They perform consistently at varying altitudes, and they’re designed with redundancies in place to prevent catastrophic failures.
- Excellent durability – High quality hydraulic cylinders are built with several durability features that make them wear and corrosion resistant. For instance, quality hydraulic cylinders are built with plated piston rods that withstand chemical attack. Some are also designed with larger springs that handle wear better and return faster.
Signs That Aviation Hydraulic Cylinders Need Maintenance
Hydraulic components are prized for their reliability and durability, but they need the occasional round of maintenance. If any of the following signs are present with your hydraulic cylinders, it’s time for a closer inspection:
- Unusual or imprecise actuator control – If your hydraulic cylinder isn’t applying consistent pressure or isn’t applying pressure at all, it needs a closer look. If there are issues with pressure application, any controls attached to the actuator will likely feel rough in the operator’s hands. This is a tell-tale sign that there could be leaks or a failing seal affecting performance.
- Unusual noises – Your flight and maintenance crews should get familiar with how your hydraulic cylinders sound during operation. They can make a good bit of noise, but it’s not the volume that’s a cause for concern, but the nature of the sound. If the hydraulic cylinder produces banging, scraping, whining or “growling” noises during operation, these could be a sign of component fatigue or cavitation.
- Visible leaks or wear – Hydraulic fluid leaks rob the cylinder of its ability to apply power, whether those leaks are internal or external. Internal leaks are usually first detected when there’s a noticeable loss of pressure. On the other hand, an external leak may be visible. At least, there may be a visible pool of hydraulic fluid present around the cylinder, indicating a leak. For small or difficult-to-detect hydraulic leaks, there are dyes that can be added to hydraulic fluid that will show up under black light.
- Overheating – An overheating hydraulic cylinder may point to issues with the cylinder rod or fluid contamination. Contaminated hydraulic fluid is the number one cause of hydraulic system failures and can alter the fluid’s viscosity if it’s bad enough. This can cascade into flow problems that manifest as changes in temperature. Persistent overheating can lead to additional problems, like accelerated component or seal wear.
In addition to the above signs, your company’s maintenance schedule is also worth considering. If it’s been a while since your hydraulic cylinders were serviced, any concerning signs should receive priority. Aviation companies understand this, which is why most maintain a detailed maintenance log for their hydraulic equipment.
Work with an Expert Hydraulic Machinery Technician for Hydraulic Cylinder Maintenance
Hydraulic cylinders play an extremely important role for aviation companies, as they are built into multiple aircraft systems and must provide unfailing reliability and controllability. If your company’s hydraulic cylinders are showing potential signs of failure or are not working as efficiently as they should, it’s time to schedule an inspection. An expert hydraulic equipment technician can provide a detailed inspection for all of your hydraulic cylinders and recommend the most cost-effective maintenance services for your equipment.